370 FARM ANIMALS 
be somewhat cooler than houses more tightly closed, but 
the air will be pure, and pure air is far more important 
than warmth. This does not, however, mean that warmth 
is not also good. 
7. Ventilation—No ventilating system compares in 
good results with one open at the front, but where one 
must be put in, it is best to have the vent near the floor 
with a tight box leading through the upper part of the 
house and through the roof. The inflow of air should 
enter near the bottom on the outside and be conducted 
to the ceiling so that it will be comparatively warm before 
it enters the house. Thus drafts will be reduced to a 
minimum and yet there will be sufficient circulation of 
air to remove moisture and impurities. Under no cir- 
cumstances should a ventilating system be given pref- 
erence over the more natural diffusion system already 
mentioned. The difficulties of making the thing work in- 
crease as the temperatures inside and outside approach 
each other, and also as the openings in the house increase. 
Piano Box CoLony Houses aT THE FARM 
Each of these houses was built of common piano boxes. They are simple, inex- 
pensive and serve the purpose as well as the more expensively constructed buildings. 
